Because they don't have to? :)

A bit more serious answer, at first developers want to focus on early stage of war or lesser known battles. Surely this has changed by the time after Chapter 4 with Operation Underground (set in 1945) and Iwo Jima (very well known) but the content support end after Chapter 6 so we don't get anything more of famous battles.

1st is what @Lamicrosz said

2nd is that it will be hella hard to balance as after the beach theres a pretty steep hill which would cause trouble for the allies to even remotely able to have a good position

Then you ask, well the allies in ww2 won that battle, well its because in ww2 they literally send 31223bajillion people there and imagine that with only 32 people, yes they can respawn but theres still a lack of people

Agreed, also most of ww2 game added Normandy and late war map in either PvP/PvE. and because of it, we can say battlefield is taking a unique turn from majorities of ww2 game, being focused on early to late war map